Fuel-injector.



UNITED ISIA'IES PATENT FFICE.

WILLIAM JOSEPH STILL, 0F LONDON, ENGLAND.

FUEL-marcaron.

I Application led July 17, 1914. Serial NoL 851,583.A

To all whom, t may concern:

Be it known that I, WILLIAM JOSEPH STILL, a subject of thel King of Great Britain, and a resident of London, England, have invented certain new and useful Improvements in Fuel-Injectors, of which the following is a specification.

This invention relates to an improved fuel valve for internal combustion engines and has for lits object to provide a fuel valve which will insure a vmore perfect atomization of the oil delivered to the combustion chamber and will obviate dangerous preignition by preventing leakage of oil into the cylinder at improper periods. A further object of my invention is to prevent the retention of admixtures of fuel and air within the valve betweenthe injection and thus enable higher valve temperatures to be attained without carbonization within the valve passages.

The primary feature of the invention consists in providing aL valve wherein a current of air passes through or over the fuel'valve and into a combustion chamber when the valve is first opened,.the' airbeing supplied at a pressure greater than that within the cylinder, the fuel to be atomized is injected into this air current and the air supply is continued after the injection of fuel has ceased so as to insure the'cleaning out of the valve passages.

According to vention the valve is operated by pressure from a fuel pump so timed as to deliver fuel during the required periods only.

In the accompanying drawings I have illustrated a valve constructed and arranged in accordance with my invention.

In these drawings Figure 1 is a sectional elevation, and Fig. 2 a sectional view of, a special form of check valve which may in some cases be employed.

vReferringto these drawings the numeral. l designates the valve casing which is bored' to receive the valve proper 2 having a conical end 3 which normally closes the ejection jet 4. Suitably located I provide a valve operating plunger 5 which also operates to,

control ,thel liow of liquid fuel from the source of supply to the valve barrel by Specification of Letters Batent.

further features of my in- Patented Apr. 9, 1918. l

7 is connected to the fuel supply and the fuel supply is delivered to this passage under pressure from a suitable pump operated by a cam or some other device driven by the engine and the operation of this pump is so timed as to deliver the. liquid fuel to the' passage 7 only at the required periods. passage 8 leads from the compressed air supply, which may be derived from any suit-l 4 able f orm of air compressor, the air passes from this passage 8 by way of the passage 9, an annular passage 10 and the orifice 11 to the valve barrel. A lever'12 is pivoted at 13 to the end of the valve 2 remote from the 70 ejection jet and ythe end 14 of this lever fulcrums upon the casing 1 as lshown and the other end 15 of this lever coperates 4With thel plunger 5 and a slight clearancev is allowed between the lever and the plunger to insure the proper closing of the valve. A headed plunger 16 controlled by a spring 17 resists the ymovement ofthe lever 12 and the valve operating plunger 5.

The operation of the valve as a Whole is as followszLiquid fuel under pressure is intermittently supplied to the passage 7 and this liquid operates to move the valve operating plunger 5 against the influence 0f the spring 17. The movementl of the plunger 15 through the medium of the lever l2 operates the valve proper 2 and a stream of air immediately rushes out of the jet 4. When the plunger-5 has moved sufficiently the .fuel

injection orifice 6 is uncovered and liquid 90 i fuel passes through the orifice into the valve barrel and is moved with the air stream and the -mixture is ejected from the jet 4 as will rbe readily understood.

In order to insure the more effective mixi ing of the fuel-and air I may provide baiing devices in the form of toothed wheels 36 arranged side by side upon the Valvespindle -as shown. The delivering of fuel, to the passage .7 ceases and the plunger 5 returns 100 p to' its normal position and the fuel orificeis closed before the valve proper 2 closes so that air continues to pass through the valve after the fuel charge has been ejected and tends to clear the liquid fuel from the valve.

The valve 2 is closedlboth by spring and air pressure but the eifective value of the latter is reduced at the correct period yfor its openin by the compression pressure inside cyli opened at this time-sd more rmly shut at other times.

The i.'

er, this rii'akes it more readily' 110 If through dirt under 'its seat, or other causes, the valve 2 should leak, oil will even then be injected into the cylinder only at or about the proper period.

This is provided for in a two-fold manner, first (in the normal condition of the jet) the port 6 is still, despite the leaky condition of the valve 2, held closed except during the proper injection periods by the piston 5 and thus the leak into the cylinder between these periods is of air only.

Secondly should the piston 5 jam (a far more improbable condition) and hold both valve 2 and piston 5 open oil can still only -be injected into the air current passing the lorifice 6 during the delivery stroke of the as a delivering valve, or a special lost motion shown in Fig. 2 is provided with a lost mo' tion device which allows the piston 5 tol valve may be fitted to the oil pump of suchl a form that it allows of the return of a proportion of the oil delivered through it back into the pump before closing. A convenient form ofvalve is illustrated in Fig. 2.

The check valve shown in Fig. 2 displaces the ordinary check valve which is now employed on the delivery side of the feedpump. The ordinary check valve would, if

employed in this instance, prevent the re-` turn of the piston and consequently that of the valve 2 tothe position in which it is shown by the imprisonment Vof liquid between it and the piston. The. check valve return.

This' valve comprises essentially a casing 18, a double valve 19, 20, a'hollow piston 21,

a hollow plug 22 serving as a stop for the piston 21 and as a guide for the tail 23 of the valve 19, 20, this plug screwing into the casing 18, a locking ring 24 and two springs 25 *and 26.

` The right hand port 2'? of this valve is coupled to the delivery pipe of the feedpump and the left hand port 28 to the port 7 of the fuel valve by a pipe. .The oil delivered by the pump lifts the valve 20 off its seating, the piston 21 following the valve 19 under the influence of the spring 26 until 1t 1s arrested bythe plug 22. As soon as the piston 21 is arrested, the valve 19 is lifted and the oil has a clear passage. As soon as the delivery from the pump ceases the-valve 19 seats upon the piston and thus prevents any back-flow of liquid. During the suction stroke of the pump the forces acting on the piston 2l are unbalanced. Consequently it is driven, by the superior force of the spring 25 acting on the piston and the imprisoned liquid, to the right until 'someof the oil yis withdrawn from the pipe leading to part 7 and the valve 2 becomes seated.

.The dimensions of the valve 2O are such that, during perfect working, it does not become seated but stops slightly clear of its seat. lf there should be some air in the oil, however as soon as an air bubble is formed on the delivery side of the check valve, thus rendering the fuel ycapable of expanding, the valve 20 seats during each suction stroke of the pump, thus checking any possible back-flow past the valve 19.

rllhe duration of time `and therefore the degree of air sweeping done at opening of valve and also at closing can be controlled by the position of the port and shape of the cam driving the oil pump, the latter control will modify the comparative duration of the opening and closing periods.

It will be understood that the particular construction of fuel valve hereinbefore described and illustrated is given by way of example and may be varied in many details within the scope of the claim.

What I claim and desire to secure by Letters Patent is An apparatus for injecting liquid fuel into a gas enginecomprisingjin combination a casing having' a jet opening and an air ypassage leading thereto, a valve member for normally closing said jet opening and arranged in said passage, said casing having a fuel orifice leading into said passage, a

`plunger' adapted to be operated by the presjsure of the liquid fuel and normally closing said fuel orifice, a lever for transmitting motion from said plunger to said valve member to open the valve, and a check valve for the fuel pump adapted torelieve the pressure behind said piston upon the intake stroke of the fuel pump whereby said piston is free to assume the position to cut o the i said orifice.

In testimony whereof l aiix my signature in presence of two witnesses. WLLIAM JOSEPH S'llLL.

Witnesses:

EDWARD A. Een, H. D. JAMESON. 

